Measured-service telephone system



sept. 1, 1925.V 1,551,597

J. WICKS 1151151111111: sEnv'IcE TELEPHONE SYSTEM Original Filed Jan. 19, 1920 2 Shoots-Sheet 1 VLSS i Sept. 1, 1925. 1,551,597

J. wlcKs nmsunsn sERvIcE TELEPHONE sYsTM Orizinal Filed Jan. 19, 1920 2 shuts-smet 2 -mfen Uff- .Patented Sept. 1, v1925.- n

vUNITED STATES JOHN wrcxs, or oAx Pm, ILLINOIS, AssrGNoR To AUTOMATIC ELECTRIC coureur,

PATENT oFFi-CE.

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

mEAsUnEn-snnvrcn TELEPHONE SYSTEM,

Applicatie mea January 19, 1920seria1 m. 352,420. Renewed January as, 1925.'

A To all whom t may concern:

Be it known that I, J oHN Wicks, a citizen of the United States of America, and resident of Oak Park, Cook County, I1linois,`

have invented certain new and useful Improvements in Measured-Service Telephone Systems, of which the following is a Specifcation.

My invention relates in general to measured service telephone systems and more particularly to automatic measured service ,systems of the type in which paystation ap paratus is provided at each subscribers station requiring the deposit of a coin to pay enabled to clear his calling devicefor use in for each successful connection. In a roposed arrangement, and one which has een used to some extent, the calling devicevat' the subscribers station isnormally inoperative to control the central office switches, and it is only byfirst depositing a coin in the paystation apparatus that the subscriber 1s operating the central oiice switches to set up a connection with a calledline. Thereafter the deposited coin is either collected or refunded depending on whether the called subscriber does or does not answer his telephone and is refunded in any case if the called party is an operator or oflicial at the l telephone office.

In such a system, the calling device is inoperative for any purpose until a coin is `is prevented because of the lack `of an indeposited. The system is open to the objection that a coin .of proper denomination is absolutely required before any connection can be established, even to an. operator, and if the subscriber does not happen to have the proper coin at haml, hefis entirely without recourse. Great damage might be done where in an emergency it is necessary to acall the fire or police dept. and such connection significanty coin.

In order to overcome this difficulty, I have devised a measured service system operating along the same general lines as the system described, but in which only a certain plurality of the switches require the deposit of a coin before they can be operated, and in which one or more switches of this type are necessarily included in every connection which is extended to another subscribers line. Other switches having a slightly different circuit are provided which are operable Without l'depositing a coin, and the trunkmg arrangement is such that a connection to an operator maybe established exclusively through these latter switches. Thus 1n my improved system a calling subscrlber may obtain connection with an operator at anytime without depositing a coin,

while if the connection is to be extended to another subscribers line a coin must be de-A posited and it maybe stated that the provision of a system havin these characteryistics is the principal object 4of the invention.-

vision `of a repeater circuit having an improved circuit arrangement for collecting and refunding deposited coins, and providvided a well known type of coin collecting mechanism, which may be of the type shown and described in the United States Patent to Forsberg, No. 1,043,219.

The line conductors 21 and 22-extend to the exchange where they terminate in theindividual line switch or trunk selector C, which is of the well lmown rotary type in which the wipers always remain on the contacts last used, and whose function it is to extend the line when calling to a trunk line vwhich terminates in an idle first selector switch. One of the trunk lines to which the line switch C has access is shown extending to the first selector E, Fig. 2.v The relay equipment in Fig. 1, which is indicated by reference character D, is a repeater, there Other objects have to do with the pro-` sov being one such repeater inserted in each first selector trunk.

The first selectors are the rst in the series ofl numerical switches which may comprise rst selectors, second selectors, and connectors, which 'are used to complete conf I nections between calling and called lines.

CJD

Cil

The reference characters F and H indicate, respectively, a second selector and connector. 'The second selector F is substantially like the first selector E, and since these selectors and also the connectors are well known in the art, it has not been thought necessary to show the complete circuits. The substation A (Fig. 2) is one of the stations to which the connector H has access and may be similar to the substation A, although rfor convenience the measured service equipment has been omitted.

- It is customary in automatic exchanges to provide a special group of second selectors through the medium of which calling subscribers may connect with the various groups of trunk lines extending to the different operators and employees at the telephone exchange, such for example as the infor-l mation operators, the trouble operators, or the wire chief. These special second selectors are generally accessible from a certain level in the regular first selectors. In Fig. 2 a trunk line is shown which terminates in a set of bank contacts in the second level of the first selector\E and which extends to a second selector F. The second selector F is one of a group of special second selectors which have access to the groups of trunk lines above referred to.y One of these trunk lines is shown in the drawing and terminates in the operators equipment indicated by the reference character Owhich comprises a group of relays, an answering jack J, and a call signal lamp L.

In order to explain the operation of the -circuits it will first be assumed that the subscriber at substation desires to Vcall the operator having the equipment O, it being possible to accomplish this without depositing a coin as has been mentioned hereinbefore. When the receiver is removed at substation A a circuit is completed for the line relay 23 of the line switch C in the usual manner, and upon energizing, the line relay closes at its armature 30 a circuit which extends from ground through the windings of the switching relay 24 and the stepping magnet 25 to battery. At the same time relay 23 connects the test wiper 36 to the above circuit at a point midway between the switching relay and t-hey said stepping initiated the wipers of the line switch C were standing as shown in the drawing, in connection with the trunk line extending to the first selector E, and we may assume furthermore that this trunk line was idle. Under these circumstances when the receiver is removed the energization of the line relay 23 isfollowed immediately by the energiza tion of the switching relay 24, which is of sufficiently high resistance to prevent the energization of the stepping magnet; and

` as a result of its energization the switching relay disconnects the line conductors 21 and 22. from the winding of the line relay and from ground, respectively, and extends them by way of armatures 26 and 28 and their Working contacts, wipers 35 and 37, bank contacts 38 and 40, armatures 63 and 65 and their resting contacts, armatures 76 and 79 and their resting contacts, and the upper and lower windings of differential relay 54 to the windings of the line relay 57 and the impedance coil 62, respectively.

Following the extension of the line as above described by the operation of the linel switch C the line relay 57 of the repeater D is energized over the line circuit and at its armature 85 completes a circuit for the slow acting relay 58. Upon energizing, relay 58 completes a holdin circuit extending baclrto the line switch C over the following path: Ground at G3, working Contact of armature 88 and the said armature, winding of low resistance relay'55, conductor 98, test contact 39, test wiper 36, armature 27 and its working Contact, winding of the switching relay 24, and the winding of the stepping magnet 25 to battery. It is understood that the abovev circuit is established before the line relay 23 has had time to deenergize. Relay may be of about 50 ohms resistance and is low enough so that the multiples ofthe test contact 39 are made busy to other rotary line switches. lThe .slow acting relay 58 also prepares a'circuit for relay 61 at its armature 87, closes the circuit of the lower winding of the electro polarized relay 59 at its armature 89, and at its armature 90 closes a contact in a special shunt circuit which will be described later on.

When the line relay 57 of the repeater was aenergized a bridge was closed across the trunk conductors 101 and 103 which may be traced as follows: Conductor 101, armature 92 and its resting contact, normally closed Contact springs controlled by armature 76, upper windingof electro, polarized relay 59,

impedance coil 60, conductor 99, and arma ture 86 and its working cont-act to trunk conductor 103. Upon the closure of the bridge as above traced the line relay 104 of the first selector E is energized in the usual manner and closes the circuit of the slow acting release relay 105. Upon energizing the relay 105 prepares' the first selector for operation in its vertical movement, and also closes the usual holding circuit extending back to the preceding switch, the circuit being traceable as follows: Ground at G4, armature 151 and its working contact, resistance X, conductor 102, and the resting contact ofarmature and the said armature to conductor 98 where it joins the previously described holding circuit extending back to the switching relay 24 of the line switchC It will be seenthat the hold- .ingcircuit is supplied with round from two points, both from G3 ,and 4, and it should be mentioned in this connection that the resistance X is approximately equal to the resistance of the relay 55 of the repeater D. It follows that the circuit through relay 55 will continue to supply approximately one.

half the 4current tothe holding circuit after the line has been extended to the selector E and relay 55 will therefore remain energized.

Before proceeding further with the `explanation, attention is called to a shunt Vcircuit around the armature 86 and its working contact which, it may be mentioned, are the impulse springsof the repeater D which control the operation of the selector E and succeeding switches. This shunt circuit ex tends as follows: From armature 86 by. way

of a section of conductor 99,'the resting contact of armature 81 and the said armature,

resting contact of armature 84 and the said armature, and the working contact ofarmature and the said armature to the working contact of the said armature 86. The

contact at armature 90 is closed, but since,

relay 55 lis energized armature` 81 will beattracted and the shunt circuit will be open at that point, it being clear from this that the shunt circuit will not interfere with the action of the impulse springs represented by armature 86 and its working contact inrepeating impulses. y,

The calling subscriber at substation A may now operate his calling device in accordance with the first ofthe two digits which yitislnecessary `to -call in order to obtain connection with the desired operator. By the operation of the calling device a series of interruptions is produced in the circuit of the line relay 57 in the well known manner, thereby causing a series of deenergizations of this line jrelay, which at each 'deenergization retracts its armature` 86 to interruptthe circuit ofthe line relay 104 of the rst selector E. l At the first deenergization relay57 sends an impulse of current throughthe w'indingof the slow acting relay 61 which isv energized and which re-v mams energized vthroughout the series of deenergizations. Relay 61, in operated position, closes at its armature 92 a direct bridge across the trunk conductors 101 and 103 `which includes only the armature, 86 of relay 57 .and its working contact, and also at its armature 93 short circuitsthe impedance coil 62. These circuit changes are brought about in ,order to reduce the resistance and impedance of the-switch control circuits toa minimum during the transmission of impulses. Proceeding now. to the selector E at each interruption of its circ'uit the line relay 104 deenergizes and transmits a current impulse through the vertical v magnet 110 to battery, the vertical magnet being operated in the usual manner to raise the shaft ofthe switch step by step until the wipersstand opposite the bank level in whichgare terminated the trunk lines extending to the special second selectors, one of which is the selector F. The slow acting relayV 106 which is in series with the vertical magnet is energized at the rst impulse and retains its armature attracted while the vertical magnet is being operated. At the first upward movement of the shaft a circuit is completed which extends from ground Gr4 by way of armature 151 and its working contact, armature 152 audits working contact oft normal springs 113, and the winding of ,the stepping relay 107 to, battery. The stepping relay 107 is accordingly energized and closes a locking circuit for itself at its arma- I ture 153. At the end of the vertical operation of the switch the slow acting relay 106v is deenergized, thereby closing a circuit for the rotary magnet; 108, the circuit being readily traceable from armature 152 by way of its resting contact, armature 154 and its 100 working contact, and the winding of the rotary magnet 108 to battery. Upon energizing, the rotary magnet 108 operates to advance the wipers 130432, inclusive, into engagement with the first set of bank contacts in the level opposite which they were raised in the vertical movement .of the switch, and alsobreaks the locking circuit of the stepping relay 107., Relay 107 thereforek deenergizes and Ybreaks., the circuit of 110 Vthe rotary magnet 108, which accordingly retracts Vits armature and again closes the ."interrupter contact controlled thereby. The operation now'depends uponwwhether the n test wiper 131 is 'inendagement with a busy 115 test contact or not. I the test contact with which` the wiper 131 has made connection is lbusy it will be grounded, and the stepping relay 104 will again be energized over a circuit which includes 4the testl wiper 131,120v

relay. This operation, by which the step- G I tact 137 it will find no ground potential and,

the stepping relay 107 will not again be energized. Instead, the switching relay 109 which was connected in series with the stepping relay 107 upon the closure of oi' normal springs 113, and which until now has been short circuited, will energize with the result that the trunk conductors 101 and 103 are disconnected from the windings of the line relay 104 and are extended by way of wipers 130 and 132, bank contacts 136 and 138, trunk conductors 141 and 143 to the double wound line relay 200 of the second selector F.

Line relay 200 is accordingly energized and closes a circuit for the slow acting release relay 201. Upon energizing relay 201 prepares the circuit of the vertical magnet at its lower armature in the usual manner and also completes the usual holding circuit which maybe traced over the following path: Ground at G5, upper armature of relay 201 and its working contact, resistance X', conductor 142, test contact 137, test wiper 131, and armature 155 and its working contact to conductor 102, where it joins `the 'holding circuit previously described. A

branch of this circuit extends from conductor 102 by way of the winding of switching relay 109, the interrupter contact of the rotary magnet 108, of normal springs 113, and the winding of the stepping relay 107 to battery. Current iow over this branch serves to maintain the relay 109 energized thus retaining the selector Ein operated position.

The calling subscriber may now operate his calling device in accordance with the second digit in the numbemthereby producing a second series of interruptions in the line circuit which are repeated as before by the relay 57 of the repeater D to produce in this case a series of interruptions in the circuit of the line relay 200 of the'second selector F. The selector F is exactly like selector E and its operation will not be described in detail. Itwill be sutlicient to say that the shaft is raised step by step until the wipers 220-222, inclusive, stand opposite the level of bank contacts in whichare terminated the trunk lines extending to the wanted operators position, after which the Wipers are` automatically rotated in search of an idle trunk line. Assuming that the trunk line shown in the drawing is the first trunk line found t o be idle the switch and it will first wipers will finally be brought to rest in engagement with bank contacts 233-235, in-

clusive, whereupon the switching relay 203 G, working contact of armature 253 and the said armature, resistance X2, bank contact 234, test wiper 221, and armature 204 and its working contact to the conductor 142 where it joins the holding circuit previously described. The switching relay 203 is maintained energized by current flow in a branch circuit similar to the one describedV in the case ofrelay`109 of selector E.

The required connection has now been established. The operator is provided with vsuitable cord circuits and other connective apparatus and when she perceives the lighted lamp L she will answer the call by inserting the answering plug of one of her l cord circuits in the jack J. From this point on the operations may take any desired course, depending upon the wants of the subscriber, and will not be described. Disconnection is effected in the usual manner by the hanging up of the receiver at substa- .tion A. This operation causes relay 57 of the repeater to deenergize with the result that the slow acting relay 58 of the repeater is deenergized to disconnect ground Ga from the holding circuit. Relay 57 also opens the bridge across thetrunk conductors 101 and.

103 with the result that the relay 250 at the operators position is deenergized, followed by' the deenergizatin of the slow acting relay 251. This latter relay removes ground G from the holding circuit. The switching relays in the selector switches and -in the line switch` C` now deenergize and the switches are thereby restored to normal position in the usual and well known manner.

`Operations in the repeater D which takeplace upon-disconnection and which have to do with the collection andVv refunding of coins are of no importancein' the case of a connection of the class just described, and will therefore 'be explained later on.

I will nowdescribe'the operation of the circuits in callin' another subscribers line,

e assumed that a connection of this kind is attempted without depositing a coin in the com collector. Assuming that the call is initiated by the subscriber at the substation A as before and that -the'desired lines the line of substation selector E are raised opposite a bank level" A', Fig. 2, when the receiver is removed at medium of the line switch- C and the repeater D to the first selector E are identical with the operations described in the previous case and will not be repeated. The operation of the selector E by which the connection is further extended to a second selector likewise have already been described and in this case there is nothing new in this operation except that the wipers of the in which are terminated trunk lines which extend to second selectors of the regular trunking system. vThe second selector F is a selector of this class and it will be assumed that the trunk line extending thereto is the first trunk line found to be idle and that the selector E established connection with the bank contacts 13S-135, inclusive. The trunk conductors 101 and 103 will now be extended b the operation of the switch-- ing relay 109 y way of wipers 130 and 132, bank contacts 133 and 135 and the upper and lower armatures of switching relay 182 tothe upper and lower windings of the line relay 180 ofthe selector F. Upon energizing, relay 180 closes the circuit of the slow acting release relay 181. Upon attracting its armature 170 relay 181 closes a holding circuit as follows: Ground at G7, armature 170 and its working contact, conductor 171, test contact 134,. test wiper 181, armature 155 and its working contact, conductor 102, and the resting contact of armature 75 and the said' armature to conductorg98 where it joins the branch extending from ground G3 at the repeater D. It will be observed that the circuit above traced vcontains no resistance, such as the resistance X, and as a result relay 55 at the repeater D is practically short circuited. This relay therefore is deenergized and at its armature 81 closes the previously described shunt circuit around the armature 86 of relay 57 and its working contact, thereby rendering the said armature 86 ineffective to open the bridge across trunk conductors v101 and 103 when relay 57 is deenergized. When the calling subscribed now operates his dial in accordance with the next digit and produces another series of interruptions in the line circuit, the resulting deenergziations of theomitted.` It follows then that whenever it is attempted to use a switch of the latter class under the circumstances just' described,

where no coin has been deposited, the relay corresponding to relay 55 of the repeater. in use will be short circuited and deenergized to disable the operating circuit extending to the switch ahead, thus preventing further extension of the connection.

I will now describe the case where the subscriber at substation A deposits a coin before calling, and in this connection will also explain briefly the process of collecting the coin at the termination of the conversation. It will be assumed that the subscriber at substation A desires to establish connection with the subscriber at substation A. The first operation is to deposit a coin of suitable denomination in the coin collecting .mechanism provided for that purpose. This nected from the line conductor 22 to ground.

The coin is held in suspense by a trap door, where it is adapted to be either refunded or collected under control of the polarized magnet. The coin may be deposited either before or after the receiver is removed. YInY either case the latter operation brings about the operation of the rotary line switch C whereby the line is extended to an idle se-r lector switch. Assuming that theselector E, Fig. 2, is the switch to which the connection is extended the operations are the same as have already been described and will not be repeated. Vith one exception, however. When the line conductors 21 and 22 are connected by the operation of the line switch C with the windings of the relay 57 and impedance coil 62 of the repeater D the ground on the line unbalances the differential relay 54 which is included in the circuit and causes this relay to operate. It may be stated that the polarizedmagnet at the substation is of high resistance and does not materially interfere with the transmission of operating impulses or with talking circuit, but is nevertheless sufficient to unbalance and cause relay 54 to energize as described. Upon attracting its armature 8O relay 54 closes a circuit for relay 56, which relay establishes a locking circuit for itself at its armature 83. Relay 56 also grounds the holding circuit extending `back to line switch C at its armature 82, and at its armature 84 opens the shunt circuit varound the impulsing springs represented by armature 86 and its working contact. This latter operation is the important thing to be considered at this time, for it obviously permits any of the switches in the exchange to be scribed, and the second selector F and connector H willbe operated in the well understood manner in response to the calling of the remaining digits to completethe connection to the desired line. Thereafter suitable ringing mechanism is operated automatically -to signal the called subscriber. When the receiver is removed at the'called station talking current is supplied to the transmitter thereat through the windings of the double wound back bridge relay 300 of the connector which relay, upon energizing, reverses the connections of the incoming line conductors in the usual manner. The direction of current flow inthe bridge at the repeater D is therefore reversed causing 'the electro polarized relay 59 to operate and. close at its armature 91 the circuit of relay 53.` Upon energizing, relay 53 establishes a locking circuit for itself at its armature 78, and at itsarmature 77 completes a circuit for the slow acting relay 52. The latter relay, upon energizing, separates conductor 102 from the holding circuit extending back to line switch C at its armature 75,

y and at its other armatures effects certain cirl armature 76, and the line relay 301 of the connector switch isnow maintained enere gized by current flow over a complete metallic circuit includingthe calling subscribers line. Relay 100, which was connected in bridge of trunk conductors 101 and 103 by the operation of relay 53, is of very high resistance (12,000 ohms or more) and being marginally adjusted, does not energize asY long. as the line circuit is closed at the call- A ing station.

When the conversation is finished both subscribers will hang up their receivers. When the receiver is replaced at substation A, the shunt around relay 100 is opened and the said rela-y will accordingly ener ize by current flow from the line relay of t e con.- nector H. Upon attracting its armature, relay 100 opens the conductor 102 and thereby breaks the locking circuit of relay 53, which deenergizes and disconnects relay 100 from in bridge of the trunk. Since the line is now open at substation A the line relay 57 of the repeater will not again be energized and the bridge including the upper winding of the polarized winding relay 59 and the impedance coil 60 will not be reestablished, from which it follows that the relays 301 and 302 of the connector H will deenergize. The latter relay ground from the holding circuit extending back in the direction of the calling line and also brings about the release of the connector switch. The removal of ground from the holding circuit permits relays 109 and 182- of selector switches E and F to deenergize, whereupon these switches are restored to normal by their release magnets in the usual manner.

At the repeater D, when relay 53 Was deenergized the said relay, in addition to operations already described, closed a circuit at its armature 77 for the slow acting relay 50. Upon energizing, relay 50 breaks the locking circuit of relay '56 at the resting contact of its armature 64 and at the working contact of the same armature connects ground to conductor 98 in order to prevent the release of the line switch C. In addition, at armatures 63 and 65, relay 50 opens both sides ofthe line and at the working contact of the latter armature' connects the battery B2 to the line conductor 22 over the following path: Line conductor 22, arma-. ture 28 and itsworking contact, wiper 37, bank'contact 40, armature 65 and its Working Contact, winding of slow acting relay 51, armature 72 and its working contact, armature 71 and its resting contact, and resistance lamp to the battery B2. Upon the closure of the above circuit current flows from battery B2 through the relay 51 and the polarized magnet at the substation A in series to ground, energizing both the relay 51 and the said magnet. Relay 51 closes at its armature 66 a circuit for the relay 97, closes a locking circuit for relay 52at, its' armature 67, and at armatures 68 and 69 connects both the incoming line conductors together and by Way of a condenser. to ground. Ordinarily the polarized magnet at substation A will respond at once to current from battery-B2 and will operate to collect the deposited coin and restore the entire coin collecting mechanism to normal condition, incidently/ disconnecting itself from the line. conductor 22. However, it sometimes happens that the armature of the polarized magnet will stick and the relay 97 isv provided to ensure the collection of of collect it.

in the circ-uit, with the object of intermit` tently energizing the polarized magnet, this operation being generally effectiveto free the armature in case it should stick. When the circuit is: inally broken permanently bythe operation of the polarized magnet and its disconnection from the line, slow acting relay 51 will deenergize .and break,

the locking circuit of slow acting relay 52. The latter relay upon deenergizing breaks the circuit of the slow acting relay 50, which upon deenergizing removes ground fr onf conductor 98, thus permitting the switching relay 24 of line switch C to deenergize. All the apparatus will now be in normal condition and ready for another call.,

In case the called subscriber did not answer it will be necessary to refundthe deposited coin rather than collect it, when the calling subscriberl replaces his receiver, and this refunding operation will now be explained briefly. Since the called subscriber did not answer neither the polarized relay 59 or relays'52 and 53 of the repeater D will be energized butthe line relay 57 and the slow acting relay 58 will be energized. Now when the calling subscriber hangs up his receiver relay 57 deenergizes and closes a circuit for the slowacting relay 6 1 and at the same time breaks the circuit of the slow acting relay 58. When the latter relay deenerglzes a circuit is completed at its" armature 89 which extends by way of armature y 94 of relay v61 and the winding of slow acting relay to batte?. Upon energizing, relay 50 operates as efore described, except that in the presentl case, sincel relay 52 is deenergized, battery B is connected 'to line conductor 22 instead of battery B2. Current low from battery B nonTv operates relay 51 and the polarized magnet at 'the substation in series, the latter being now actuated to refund t-he deposited coin instead Upon energizing, relay 51 completes a locking circuit forv relay 50 at its armature 67, and produces other .circuit changes which have already been described.y

- When the circuit is broken by the discon- `neet-ion of the polarized magnetat the substation, relay 51 deenergizes followed by the deenergization of relay 50, and the release ofthe lineswitch C, whereupon all the ap- ,pa-ratus will have been restored to-normal.

While I have described a certain specific embodiment of my invention I recognize..

that'the same may bevmodiied to adapt it for use in connection `with other typeslot` automatic switching mechanism andi,vl with other types `ofmeasuredy service equipment;

I do not wisl therefore to be limited to the precise-form herein disclosed, but deslreto secure and have protected by Letters Patent all forms of my invention which may hereinafter be devised, limited only by the scope of the appended claims.

What I claim as my invention is:

1. In a telephone system, subscribers lines extending to a central exchange, measured service equipment at the station on each line, an impulse sender at the station on each line independent of the associated measured service equipment, automatic selector switches of two classes at the exchange, said switches controlled by said senders, and means at the ,exchange for rendering the switches of one class operable only under control of said equipment, and the switches of the other class operable independent of said equipment.

2. In a telephone system, a subscribers line extending to a central exchange, coin collecting mechanism at the station-on said line, automatic selector switches at the exchange normally uncontrollable from said station, means at the exchange effective only after a coin hasbeen deposited in said mechanism for permitting said selectors to be controlled from said station, and otherselector switches at the exchange controllable from said station without depositing a coin.

3. In ya telephone system, subscribers lines, automatic switches controllable over calling subscribers lines for connecting with called lines, discriminating equipment at the exchange, measured service apparatus at the station on each line requiring the subscriber to charge himself with a call to eliect the operation of said equipment before a connection can be set up by means of said switches, an operators position, and other automatic switches controllable over calling lines for connecting with said operators position without charge.- f

4. In a telephone system, a calling .and a called subscribers lines, an automatic switch controllable from the station on the calling line to complete a connection with said called line, paystation equipment at the-calling station, means at the exchange requiring 'a'coin to be deposited'in saidpaystation before said switch Ican be operated, any operators position, another automatic switch, and means individual tosaid second switch rendering the same controllable from said station to complete a connection to lsaid operators position without depositing a stations, paystation equipment at each of said substations, an operators:position,'au-

tomatic switchesof two classes for completing` connections to subscribers .lines and to .said operators position, respectlvely, circuit arrangements at the exchange common to all .said'switches and such that a coin-must be deposited in the paystation at acalling `staerating certain of said switches, and resistances included in the release trunk conducel tors associated with certain other of said switches, whereby such switches may be' operated free.l`

7. In a measured service telephone system, a repeater and associated first selector switch at the exchange, trunk lines accessible to said switch each terminating in a second s'elector switch, a release trunk conductor in each trunk line, resistances in the release trunk conductors extending to certain of said second selectors only, and means in said repeater for preventing a calling subscriberl from' operating those selectors whose associated release trunk conductors have no resistances unless the connection has been paid for in advance.

8. In a telephone system, a subscribers station, a paystation device at said station, automatic switches at the exchange, a repeater interposed betweensaid line and switches, a control circuit extending from said repeater for operating said switches, and means in certain of said switches for rendering said control circuit linoperative unless acoin has been deposited in said device.

9. In a telephone system, a subscribers station, a paystation device at said station, automatic switches at the exchange, a repeater interposed between said line and switches, a control circuit extending romsaid repeater for operating said switches, an operators position accessible to certain of said switches, a called subscribers line accessible to certain other of said switches, and means in the said latter switches only for rendering said control circuitinoperajtive unless a coin has been deposited in said device.

10. In a telephone system, a subscribers line extending to a central exchange, coin collectin mechanism at the station on said line, serlally related automatic switches at the exchange, a repeater interposed between the said line and switches, a normally .inf operative' control circuit extending from the repeater to the first one of said switches, and means responsive to the deposit of a coin in said mechanism for rendering said circuit operative.

11. In a telephone system, a subscribers line extending to a central exchange, coin collecting mechanism at the station on said -the said line and switches, a control circuit extending from the repeater to one of said switches and including interrupter contacts for controlling the same to operate said switch, a shunt path around said contacts,

and means responsive to the deposit of a' coin in said mechanism for opening said shunt. f

12. In a telephone system, a subscribers line extending to a central exchange, coin collecting mechanism at the station on said line, serially related automatic switches at the exchange, a repeater interposed between the said line and switches, a normally inoperative control` circuit extending from the repeater .to the first one of said switches, means in said repeater for rendering said circuit operative when -the line is calling, and means in another switch in the series for rendering said circuit again inoperative.

13. In a telephone system, a subscribers line extending to a central exchange, coin collecting mechanism at the station on said line, serially related automatic switches at the exchange, a repeater interposed between the said line and switches, a control circuit extending from the repeater to one of said switches and including interrupter contacts for controlling the same to operate said switch, ay shunt path around said contacts, means in said repeater for opening said shunt when the said line is calling, and means in another switch in the series for again closing said shunt.

14. In a telephone system, a subscribers line extending to a central exchange, coin collecting mechanism at the station on said line, .a group of selector switches at the exchange always operable from `said station freeof charge, other selector switches directly accessible to the selectors of said group and also always operable from said station free of., charge, still other selectors directly accessible to the selectors of said group, and means at the yexchange effective only after suitable coinsy have been deposited in said Icollecting mechanism for permitting selectors of said last group to be operated.

15. In a telephone system, a subscribers line extending to a central exchange, coin collect apparatus at the station on said line, automatic switches of two classes at the exchange, impulse sending mechanism at the station on said line operable independent of said coin collect apparatus to transmit im:

pulses to the exchange, and, means at the exchangev for rendering the impulses transmitted inefective to control the switches of a certain one. of said classes unless a coin has been deposited in said coin collect apparatus, while the switches in the other class are always responsive whether a coin is deposited or not.

`16. In a telephone system, paystation lines extending to a central exchange, automatic 'paystations on the calling lines.

17. In an automatic telephone system, the combination of a calling and called telephone lines, automatic switches for interconnecting said lines, a coin collector at the calling station having a magnet, sources of uninterrupted current at the central oiiice ot different character for operating said magnet either tol refund or collect a deposited coin, means controlled by the called party for selecting the source to be connected to the calling line to selectively operate said magnet, means automatically actuated by the replacement of the receiver by the calling panty for momentarily applying cur- .rent from the selected source to the calling line, and means for thereafter intermittently app-lying said source to said line until the Goin is-refunded or collected. v

15:18. In an automatic telephone system, the

4 combination of calling and called telephone lines,'automatic switches for interconnectingsaid lines, a coin collector at the calling sta- -l gtion having a magnet, sources of current of .different character for operating said magnet, either to refund or collect a deposited coin, means controlled by the called party for selecting the source to be connected to the calling line to selectively operate said magnet, means automatically actuated by the replacement of the receiver by the calling party for momentarily applying the selected current to the calling line, and means at the exchange responsive to the momentary application of current to the calling line for causing saidmurrent rto bethereafter'intermittently applied until the coin has been collected or refunded. e

19. In an automatic telephone system, calling lines equipped with paystation mechanism, called lines of. two classes, automatic switches for partially setting up a connection to either classA of called lines, other switches accessible to said first switches Some of which other switches have access to one class of called lines while others have access to called lines of the other class, and means provided only in switches of one class making it necessary for a calling subscriber to deposit a coin in the paystation mechanism before a talking connection can be completed.

20: In a telephone system, calling, lines equipped with paystation mechanism, called lines of two classes, means including an automatic switch individual to one class of called lines for completing connections without requiring a coin to be deposited in said paystation mechanism, and means including an automatic switchv individual to the other class oflines for requiring a coin to be deposited inthe paystation mechanism before a .talking connection can be completed.

21. In a telephone system, calling lines equipped with paystation mechanism, called lines of two classes, groups of automatic switches each group having access to called lines of a different class, trunk lines accessible to the calling lines terminating in automatic switches having access to either class of said first mentioned automatic switches, and means in said trunk lines controlled by means in the automatic switches of only `one class making it necessary for a coin 'to be deposited in said paystation mechanism before a talking connection can be com leted.

22. n a telephone system, calling lines equipped with coin collect mechanism, called lines of two classes, groups of automatic switches, each group having access to a particular class of called lines, trunk lines accessible to said calling line terminating in automatic switches having access to said first switches, means in said trunk lines for preventing the establishment of connections to one class of called lines, rendered ineffective by theI deposit of a coin in said mechanism, and means in the automatic switches having access to the other class of called lines for also rendering said means ineffective.

23. In a telephone system, calling lines provided with paystation mechanism, called lines of two classes, means at the exchange including automatic switches controlled over any calling line for setting up talking connections to called lines of either class, means also at the exchange rendering the establish- 24. In a telephone system, calling lines equipped with measured service equipmentv at the station on each line, an impulse sender at the station on each line independent of the associated measured service equipment, called lines of two classes, automatic switches at the exchange,V means at the exchange requiring a coin to be deposited inasaid paystation mechanism before a connection can be completed to lines of onev Aclass, a1 1d 111981115 independent of said paystation mechanism for renderingsaid means at the exchange ineiiective when lines of the other class are called.

25. ln a telephone exchange system, calling lines provided with paystation mechanism, calledlines of diiierent classes, means for extending connections from said calling lines to called lines of all classes, and circuitY arrangements at the exchange requiring the deposit of a coin in said paystation mechanism before a talking connection can be completed to a line of a particular class.

26. In a telephone exchange system, callingl lines, paystations for said lines, called lines of two classes, means for extending connections to lines of either class, and circuit arrangementsat the exchange requiring the deposit of a coin in said paystation mechanism before a talking connection can be completed to lines 0f one class.

W. In a repeater for an automatic paystation telephone system, a trunk line ex- `Lending through said repeater and comprising two sections, a line relay bridged across the incoming section, contacts on said line relay for closiig a bridge across the outgoinssection and for interrupting the same su equently responsive to interruptions in the incoming section, a shunt around said contacts, a diii'erential relay in series with said line relay, and means controlled by said differential relay for opening said shunt.

28. In a repeater for an automatic paystation telephone system, a trunk line extending through mid repeater and comprising two sections, a line relay bridged across the incoming section, contacts on said line relay for closing a. bridge across the outgoing section and for interrupting the same subsequently responsive to interruptions in the incoming section, a shunt around said contacts, a release trunk conductor included in ysaid trunk line, a relay for opening said shunt, and a circuit o-ver which ground is connected to said conductor through the winding of said last mentioned relay.

29. In a repeater for an automatic paystation telephone system, a trunk line extending through said repeater and comprising two sections, a line relay bridged across the incoming section, contacts on said line relay for closing a bridge across the outgoing section and for interrupting the same subsequently responsive to interruptions in the incoming section, a shunt circuit around said contacts, two sets of contacts included in said shunt circuit in series, a differential relay in series with said line relay, means controlledy by said differential relay for opening one of said sets of shunt circuit contacts, a release trunk conductor included in said trunk line, a relay controlling the second of said sets of shunt circuit contacts, and a circuit over which ground is connected to said release trunk conductor through the winding ofsaid relay.

Signed by me at Chicago, Cook County, Illinois, this 14th day of January, 1920.

JOHN VVICKS. 

